Lateral access system and method of use

ABSTRACT

A surgical access device including a frame, first and second supports, and first and second retractor blades releasably coupled with the first and second supports, respectively. The frame has first and second arms. The first support is releasably coupled with the first and second arms. The second support is slidably mounted on the first and second arms. The second support is movable between a first position with the retractor blades in close cooperative position and a spaced apart position with respect to the first support. The first and second retractor blades each have a distal end portion configured and adapted to engage a vertebral body. In one method of use, the retractor is inserted through an incision in first orientation with the blades in close approximation and rotated approximately 90°, before spreading the retractor blades to retract tissue.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.13/270,588, filed Oct. 11, 2011. which claims priority to, and thebenefit of, U.S. Provisional Patent Application Ser. No. 61/391,402,filed Oct. 8, 2010, the entire contents of each of which areincorporated by reference herein.

BACKGROUND

1. Technical Field

The present disclosure is related to devices used in accessing a spinalwork location. More particularly, the present disclosure relates todevices and methods for laterally accessing a spinal work location

2. Background of Related Art

Disease, the effects of aging, or physical trauma resulting in damage tothe spine has been treated in many instances by fixation orstabilization of the effected vertebra. A wide variety of spinalfixation apparatuses have been employed in surgical procedures forcorrecting spinal injuries and the effects of spinal diseases.

After a partial or complete discectomy, the normally occupied spacebetween adjacent vertebral bodies is subject to collapse and/ormisalignment due to the absence of all or a part of the intervertebraldisc. In such situations, the physician may insert one or moreprosthetic spacers between the affected vertebrae to maintain normaldisc spacing and/or the normal amount of lordosis in the affectedregion.

Typically, a prosthetic implant is inserted between the adjacentvertebrae and may include pathways that permit hone growth between theadjacent vertebrae until they are fused together. As is typical, theintervertebral spaces are accessed either anteriorly or posteriorly. Itwould be desirable to access the intervertebral spaces via a lateralapproach.

SUMMARY

In accordance with an embodiment of the present disclosure, there isprovided a surgical access device including a frame having first andsecond arms, first and second supports, and first and second retractorblades. In particular, the first support is releasably coupled with thefirst and second arms, and the second support is slidably mounted on thefirst and second arms. The second support is movable between a firstposition with the retractor blades in close cooperative alignment and aspaced apart position with respect to the first support. The first andsecond retractor blades are releasably coupled with the first and secondsupports, respectively, wherein the first and second retractor bladeseach have a distal end portion configured and adapted to engage avertebral body.

In an embodiment, the distal end portion of the respective first andsecond retractor blades may define a recess configured and adapted toengage the vertebral body. In addition, the recess defined in therespective distal end portions of the first and second retractor bladesmay include an arcuate portion having a radius of curvaturesubstantially identical to that of the vertebral body.

The first and second retractor blades may each define a longitudinalgroove, whereby when the first and second retractor blades are in aclose cooperative position the grooves define a lumen. Moreover, thelongitudinal groove may be configured and dimensioned to receivetherethrough a fixation pin or guide wire.

In another embodiment, the first and second arms may each define alongitudinal cavity defined along the length of the first and secondarms. The second support may include a translation knob configured tomove the second support to a particular position along the first andsecond arms. The surgical access device may further include an auxiliaryblade transversely mounted on one of the first and second arms. Inaddition, the surgical access device may further include a locking wheelconfigured and adapted to secure the auxiliary blade to a particularposition along one of the first and second arms. The auxiliary blade maybe transversely adjustable.

The second support may include a ratchet assembly configured and adaptedto provide a uni-directional movement of the second support along thefirst and second arms. The retractor blade may include an engagingportion and a blade portion extending from the engaging portion. Theengaging portion may be configured and adapted to engage an underside ofthe respective first and second support. The engaging portion of theretractor blade may also include a protruding portion configured anddimensioned to be received through a cavity defined in respective firstand second supports.

In accordance with another aspect of the present disclosure, there isprovided a method of accessing the spine. The method includes providinga surgical access system including a retractor device, a dissector, aspinal implant, a guide wire, and a fixation pin. In particular, theretractor device includes first and second supports and first and secondretractor blades. In particular, the second support is movable between aclose cooperative position and a spaced apart position with respect tothe first support. The first and second retractor blades are releasablycoupled with the first and second supports, respectively, wherein thefirst and second retractor blades each have a distal end portionconfigured and adapted to engage a vertebral body. The method furtherincludes establishing a path to the spine, introducing the first andsecond retractor blades through the path, in one orientation with theretractor blades in close cooperative alignment, reorienting theretractor to a second orientation, retracting open the retractor deviceto separate the second support from the first support, therebyseparating the retractor blades mounted to the supports to retracttissue, inserting a fixation pin into a vertebral body to maintain bladeposition relative to the vertebral body, and performing surgery throughthe operating channel defined by the retracted blades. The surgery mayinclude positioning a spinal implant between vertebral bodies.

In an embodiment, introducing the retractor blades through the incisionmay include placing the first and second retractor blades in closecooperative alignment. Establishing an adequate path to the spine mayinclude inserting a dissector to the disc and inserting the guide wirethrough the dissector into the disc space.

The method may further include distracting the disc utilizing a discspreader. In addition, the method may also include inserting theretractor with the blades in close cooperative alignment and orientedalong the axis of the fibers of the psoas muscle, and rotating theretractor device so that the orientation of the retractor blades is inline with the endplates of the vertebrae and substantially transverse tothe fibers of the psoas muscle. Rotating the retractor device mayinclude rotating the retractor device to a position in which the distalportion of at least one of the retractor blades conforms to and contactsthe vertebral body.

In another embodiment, the distal end portions of the respective firstand second retractor blades may define a concave recess configured andadapted to engage the vertebral body. The recess defined in the distalend portions of the respective first and second retractor blades mayinclude an arcuate portion having a radius of curvature substantiallyidentical to that of the vertebral body, so that when the retractorblades are oriented transverse to the psoas muscle the arcuate distalend portion of each blade substantially conforms to and may bepositioned against the arcuate lateral wall of the correspondingvertebra.

The first and second retractor blades may each define at least onelongitudinal groove, whereby when the first and second retractor bladesare positioned in close cooperative alignment the grooves define alumen. The longitudinal groove may be configured and dimensioned toreceive therethrough a fixation pin. The retractor device may furtherinclude an auxiliary blade transversely mounted on one of the first andsecond retractor blades. In particular, the auxiliary blade may includea longitudinal groove. The dissector may include indicia thereon markingthe distance from a distal end of the dissector.

The method may further include forming a lateral incision, digitallyprobing the retroperitoneal space, inserting one or more dissectors toloosen tissue and form a lateral pathway to the disc space, inserting aguide wire or pin through a dissector into the disc space, removing thedissector, and mounting the retractor over the guidewire or pin byinserting the guidewire or pin through a lumen defined by longitudinalgrooves in one or both of the first and second retractor blades. Withthe blades in close cooperative alignment, the retractor blades areinserted over the guidewire through tissue with the blades oriented in afirst position along or substantially parallel to the longitudinal axisof the psoas muscle until the distal end of the retractor blades areadjacent the disc space. The blades when positioned in closeapproximation are substantially flat and capable of dividing the fibersof the psoas muscle during insertion of the blades through the muscle.The substantially flat profile of the retractor blades when in closeapproximation obviates the need to insert the retractor over any type ofintroducer structure, such as a dissector. The retractor is rotated to asecond position substantially transverse to the first position to orientthe retractor blades substantially transverse to the psoas muscle with afirst retractor blade adjacent a first vertebral body. The distal end ofthe first retractor blade conforms to the vertebral body lateralsurface. Optionally, one or more fixation pins are inserted through thelumen formed by grooves in one or both blades and driving or screwingthe fixation pin laterally into the vertebral body to fix the positionof the first blade with respect to the vertebral body. The second bladeis moved away from the first blade to form a gap between the bladeswhich spans the disc space, so that the second blade is adjacent asecond, adjacent vertebral body across the disc space with the distalend of the second retractor blade conforming to the shape of the secondvertebral body. Optionally, a second fixation pin is driven or screwedinto the second vertebral body to fix the position of the second bladerelative to the second vertebral body, thereby defining an operatingchannel extending from the skin to the disc space. Surgery on the discspace may be performed through the operative channel (which surgery mayinclude removing disc material and inserting bone or a synthetic implantin the interbody space), subsequent to which the optional fixation pins,if used, may be removed, the retractor withdrawn and the incision closedin a traditional manner. Advantageously, the retractor defines a clearopen channel unobstructed by parts of the retractor or instruments,which provides good visibility to the disc space visually and underimaging such as fluoroscopy.

The method may further include introducing an intradiscal shim throughthe groove of the auxiliary blade and into the disc space. The methodmay also include determining a blade length of the first and secondretractor blades. In addition, the method may also include placing apatient in a lateral decubitus position on an operating table.

In still another embodiment, retracting open the retractor device mayinclude positioning the second support in the spaced apart position withrespect to the first support. In addition, inserting the fixation pininto the vertebral body may include inserting the fixation pin throughthe longitudinal groove of the respective first and second retractorblades.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the present disclosure are described hereinbelowwith reference to the drawings, wherein:

FIG. 1 is a top, plan view of a retractor system in accordance with anembodiment of the present disclosure;

FIG. 2 is a side cross-sectional view of the retractor system of FIG. 1cut along a section line of 2-2 in FIG. 1;

FIG. 3 is a side cross-sectional view of the retractor system of FIG. 1cut along a section line of 3-3 in FIG. 1;

FIG. 4 is a side view of a retractor blade for use with the retractorsystem of FIG. 1;

FIG. 5 is a front view of the retractor blade of FIG. 4 for use with theretractor system of FIG. 1;

FIG. 6 is a top, plan view of the retractor blade of FIG. 4 for use withthe retractor system of FIG. 1;

FIG. 7 is a perspective view of an auxiliary blade for use with theretractor system of FIG. 1;

FIG. 8 is a perspective view of an optional table mount for use with theretractor system of FIG. 1;

FIG. 9A is a side view of a dissector for use with the retractor systemof FIG. 1;

FIG. 9B is a cross-sectional view of the dissector of FIG. 9A;

FIG. 9C is a side view of another dissector for use with the retractorsystem of FIG. 1;

FIG. 9D is a side cross-sectional view of the dissector of FIG. 9C;

FIG. 9E is a side view of still another dissector for use with theretractor system of FIG. 1;

FIG. 9F is a side cross-sectional view of the dissector of FIG. 9E;

FIG. 10 is a top, plan view of a spinal interbody spacer for use withthe retractor system of FIG. 1;

FIG. 11 is a side view of the spinal interbody spacer of FIG. 10;

FIG. 12 is a cross-sectional view of the spinal interbody spacer of FIG.10 cut along a section line 12-12 in FIG. 11;

FIG. 13A is a top, plan view of another embodiment of a spinal interbodyspacer for use with the retractor system of FIG. 1;

FIG. 13B is a rear view of the spinal interbody spacer of FIG. 13A;

FIG. 14 is a perspective view of an inserter for use with the spinalinterbody spacer of FIG. 10-12 or 13A-13B;

FIG. 15 is an exploded perspective view of the inserter of FIG. 14 withparts separated;

FIG. 16 is a perspective view of an intradiscal shim for use with theretractor system of FIG. 1;

FIG. 17 is a side view of an intradiscal shim inserter for use with theintradiscal shim of FIG. 16;

FIG. 18 is a side view of an intradiscal shim extractor for use with theintradiscal shim of FIG. 16;

FIG. 19 is a perspective view of a disc spreader for use with theretractor system of FIG. 1;

FIG. 20 is a side view of the disc spreader of FIG. 19;

FIG. 21 is a side view of a fixation pin for use with the retractorsystem of FIG. 1;

FIG. 22 is a side view of a fixation pin driver for use with thefixation pin of FIG. 21;

FIG. 23 is a side view of a guide wire for use with the retractor systemof FIG. 1;

FIGS. 24 and 25 are perspective views of the dissector of FIG. 9Aillustrating use thereof;

FIGS. 26 and 27 are perspective views of the dissector of FIG. 24 and aguide wire of FIG. 23 illustrating insertion of the guide wire throughthe dissector;

FIG. 28 is a perspective view of the guide wire of FIG. 26 illustratingthe guide wire inserted in the disc;

FIGS. 29 and 30 are perspective views of the guide wire of FIG. 28 andthe dissector of FIGS. 9C and 9D illustrating insertion of the dissectorover the guide wire to enlarge the opening in tissue;

FIG. 31 is a perspective view of the dissector and the guide wire ofFIG. 30 illustrating rotation of the dissector to free up soft tissue;

FIG. 32A is a perspective view of the retractor system of FIG. 1including the retractor blades of FIG. 4 attached thereto illustratinginsertion of the retractor system over the guide wire;

FIG. 32B is a side view of the retractor system of FIG. 32A;

FIG. 32C is a top view of the retractor system of FIG. 32A;

FIG. 33 is a perspective view of the retractor system of FIG. 32Aillustrating the retractor system advanced directly to the spine;

FIG. 34A is a perspective view of the retractor system of FIG. 33illustrating rotation thereof approximately 90 degrees;

FIG. 34B is a side view of the retractor system of FIG. 34A;

FIG. 35A is a perspective view of the retractor system of FIG. 34Aillustrating the retractor system retracted to a partially openedposition;

FIG. 35B is a side view of the retractor system of FIG. 35A;

FIG. 36A is a perspective view of the retractor system of FIG. 35A and afixation pin of FIG. 21 illustrating insertion of the fixation pin intoa first vertebra through a longitudinal channel of the retractor blades;

FIG. 36B is a side view of the retractor system of FIG. 36A;

FIGS. 37 and 38A are perspective views of the retractor system of FIG.36A illustrating removal of the guide wire;

FIG. 38B is a side view of the retractor system of FIG. 38A;

FIG. 39A is a perspective view of the retractor system of FIG. 38A in amore fully open position and the fixation pin of FIG. 21 illustratinginsertion of the fixation pin into a second vertebra;

FIG. 39B is a side view of the retractor system of FIG. 39A:

FIG. 40A is a perspective view of the retractor system of FIG. 39Aillustrating the retractor system providing access and visualization ofthe disc; and

FIG. 40B is a side view of the retractor system of FIG. 40A.

DETAILED DESCRIPTION OF EMBODIMENTS

Embodiments of the present disclosure will now be described in detailwith reference to the drawings, in which like reference numeralsdesignate identical or corresponding elements in each of the severalviews. As used herein, the term “distal,” as is conventional, will referto that portion of the instrument, apparatus, device or componentthereof which is farther from the user while, the term “proximal,” willrefer to that portion of the instrument, apparatus, device or componentthereof which is closer to the user. In addition, the term “cephalad” isused in this application to indicate a direction toward a patient'shead, while the term “cephalad” indicates a direction toward thepatient's feet. Further still, for the purposes of this application, theterm “medial” indicates a direction toward the middle of the body of thepatient, while the term “lateral” indicates a direction toward a side ofthe body of the patient, i.e., away from the middle of the body of thepatient. The term “posterior” indicates a direction toward the patient'sback, while the term “anterior” indicates a direction toward thepatient's front. In the following description, well-known functions orconstructions are not described in detail to avoid obscuring the presentdisclosure in unnecessary detail.

With reference to FIGS. 1-3, an embodiment of the present disclosure isshown generally as a retractor system 100 configured and adapted for aminimally invasive surgical procedure to access, for example, thethoracic or lumbar vertebrae. Retractor system 100 includes a firstsupport 110 having arms 130, 132 extending therefrom and a secondsupport 120 that is slidably mounted on arms 130, 132. Second support120 may be secured in a plurality of locations relative to first support110. Each support 110, 120 is configured and dimensioned to receive andsupport a retractor blade 200 (FIGS. 4-6) releasably secured thereto, aswill be discussed in detail hereinbelow. Movement of second support 120along arms 130, 132 allows retractor blade 200 on second support 120 tobe moved between a position closely adjacent to a blade mounted tosupport 110, and a spaced apart position with respect to the opposingretractor blade 200 releasably secured with first support 110.

With particular reference to FIG. 1, each arm 130, 132 is coupled tofirst support 110. Arms 130, 132 define respective cavities 133, 134that extend at least partially along the length of respective arms 130,132. Cavity 133 of arm 130 includes a portion having teeth 136 thatoperatively engage a translation knob 122 of second support 120.Translation knob 122 is configured and adapted to secure second support120 to a particular location on arm 130 upon rotation of translationknob 122. In addition, each cavity 133, 134 is configured anddimensioned to accommodate locking wheels 135, 137 translatably disposedin respective cavities 133, 134. Each locking wheel 135, 137 isconfigured and adapted to secure auxiliary blades 400 (FIG. 7) at aposition along respective arms 130, 132, as will be describedhereinbelow. While only cavity 133 is illustrated with teeth to interactwith a wheel and ratchet of the second support, alternatively or inaddition there could be teeth associated with cavity 134 to engage aratchet and/or wheel on the other side of secondary support 120.

Retractor blade 200 is releasably attachable to first support 110. Anengaging portion 202 (FIG. 4) of retractor blade 200 engages anunderside of first support 110. Moreover, first support 110 defines acavity 119 configured and dimensioned to detachably secure a protrudingportion 204 (FIG. 4) of retractor blade 200 therein. In addition, firstsupport 110 includes a locking slider 118 that slidably engagesprotruding portion 204 of retractor blade 200 to releasably secureprotruding portion 204 of retractor blade 200 within cavity 119. Lockingslider 118 is operatively coupled to a biasing member 115 (FIG. 3) suchthat locking slider 118 is biased toward a locked state. An engagingportion 121 (FIG. 3) of locking slider 118 engages a groove 206 (FIG. 4)defined in protruding portion 204. In this manner, retractor blade 200is releasably secured to first support 110.

With continued reference to FIG. 1, first support 110 further defines apair of recessed portions 112, 114 aligned with cavities 133, 134,respectively. Recessed portions 112, 114 are configured and dimensionedto accommodate respective locking wheels 135, 137 therein to enableapproximation of first and second supports 110, 120 to a closecooperative position with locking wheels 135, 137 nested in the recessedportions.

Second support 120 includes similar features of first support 110. Inparticular, second support 120 defines a cavity 129 configured anddimensioned to receive protruding portion 204 of retractor blade 200.Second support 120 also includes a locking slider 128 configured andadapted to releasably secure protruding portion 204 in cavity 129. Asdiscussed hereinabove with respect to locking slider 118, locking slider128 is operatively coupled to a biasing member 125 (FIG. 3), wherebylocking slider 128 is biased toward the engaging state. In the engagingstate, an engaging portion 127 (FIG. 3) of locking slider 128 at leastpartially protrudes through cavity 129, whereby when protruding portion204 of retractor blade 200 is disposed in cavity 129, engaging portion127 of locking slider 128 engages groove 206 defined in protrudingportion 204. In this manner, retractor blade 200 is releasably securedwith second support 120.

In contrast to first support 110, second support 120 includes atranslation knob 122 rotatably mounted on second support 120 to movesecond support 120 to a particular position along the length of arms130, 132. Translation knob 122 engages teeth 136 on arm 130, wherebyrotation of translation knob 122 moves second support 120 to aparticular position along arm 130. A ratchet engages the teeth as thesecond support is moved away from the first support to secure the secondsupport position relative to arms 130, 132, and hence also relative tothe first support. Rotation of translation knob 122 in the oppositedirection with the ratchet released moves the second support 120 alongarm 130 in the opposite direction toward the first support. In addition,second support 120 includes a ratchet assembly configured to enableuni-directional movement of second support 120 and lock the secondsupport in position along arms 130, 132. The ratchet assembly includes aratchet knob 124 that is configured to release/disengage the ratchetassembly with arm 130 to enable selective uni-directional movement ofsecond support 120.

With reference now to FIGS. 4-6, retractor blade 200 is releasably andinterchangeably attachable to first or second supports 110, 120, andincludes engaging portion 202 and a blade portion 208 extendingtherefrom. Engaging portion 202 engages the underside of respectivefirst and second supports 110, 120 in a superposed relation. Bladeportion 208 is substantially orthogonal to engaging portion 202, wherebywhen retractor blade 200 is releasably secured with respective first andsecond supports 110, 120, blade portion 208 is substantially orthogonalto first and second supports 110, 120. However, it is furthercontemplated that each retractor blade 208 may define a predeterminedfixed angle with respect to engaging portion 202 and first and secondsupports 110, 120. In use, retractor blades 200 are attached to firstand second supports 110, 120, respectively, as shown in FIG. 32A and32B. As best seen in FIG. 4, the retractor blade has a thin,substantially flat profile.

With reference to FIG. 4, engaging portion 202 includes a protrudingportion 204 configured and dimensioned to extend through respectivecavities 119, 129 of first and second supports 110, 120. In particular,each protruding portion 204 defines a groove 206 configured anddimensioned to securely engage respective engaging portions 121, 127(FIG. 3) of locking sliders 118, 128 of first and second supports 110,120.

With particular reference to FIG. 6, each blade portion 208 of retractorblade 200 includes one or more longitudinal channels 209 extendingsubstantially along the length of blade portion 208. Thus, whenretractor blades 200 of respective first and second supports 110, 120are in close cooperative alignment, opposing channels 209 of bladesportions 208 define one or more lumens for receiving, for example, aguide wire 1700 (FIG. 23), a guide pin, or other surgical implementtherethrough. The groove may be rounded and may have slightly greaterthan a 180° circumference so that a pin inserted into the groove is heldin place, although the pin may be pulled out of the groove withsufficient force.

With particular reference back to FIG. 5, a distal end portion 208 a ofblade portion 208 defines a recess 207 having a concave profile. Theconcave profile of recess 207 is adapted to engage and accommodate thecontour of a vertebral body. Optimally, the concave recess defines aradius of curvature in the range of about 0.1 inch to about 1.0 inch,and more preferably about 0.6 inch. The concave profile of recess 207improves engagement of retractor blade 200 with the vertebral body (see,for example, FIG. 40A) and, for example, reduces slippage therewith andtissue creeping under and around the blade, especially as the retractoris manipulated during surgery. The surgeon may be provided with aplurality of retractor blades having various radii of curvatures ofconcave profile of the recess defined in a distal portion of the bladeportion to accommodate various contours of the vertebral body.

With reference to FIGS. 1 and 7, movement of second support 120 alongarms 130, 132 from a close cooperative position with first support 110to a space apart position from first support 110 allows retraction oftissue in the longitudinal direction. However, further retraction in thetransverse direction can be achieved through the use of an auxiliaryblade 400 (FIG. 7). Auxiliary blade 400 includes an engaging portion 402defining a cavity 403 of varying dimensions and a blade portion 408extending from engaging portion 402. Cavity 403 of engaging portion 402is configured and dimensioned to be secured along the length of arms130, 132. Specifically, cavity 403 defines an enlarged portion 404 and anarrowed portion 406. In particular, enlarged portion 404 of cavity 403is dimensioned to receive therethrough locking wheel 135, 137 such thatengaging portion 402 of auxiliary blade 400 may be positioned on arms130, 132 in a superposed relation and secured by locking wheels 135,137. A neck portion 136 (FIG. 3) of locking wheel 135, 137 is configuredand dimensioned to be slidably received in narrowed portion 406 ofauxiliary blade 400. Blade portion 408 is substantially orthogonal withrespect to engaging portion 402, whereby when auxiliary blade 400 issecured with respective arms 130, 132, blade portion 408 issubstantially orthogonal to arms 130, 132. In addition, each bladeportion 408 includes one or more longitudinal channels 409 extendingsubstantially along the length of blade portion 408. Channels 409 areconfigured and dimensioned to receive, for example, guide wire 1700, aguide pin, or other surgical implement such as an intradiscal shim 1300(FIG. 16), as discussed below.

Under such configuration, auxiliary blade 400 may be adjustably securedto arms 130, 132. Specifically, neck portion 136 of locking wheel 135may be slidably received through narrowed portion 406 of cavity 403 toenable the surgeon to select a particular position of auxiliary blade400 in the transverse direction, as well as the longitudinal directionon arms 130, 132. Upon selecting a desirable position, the surgeon mayrotate locking wheel 135, 137 in a first direction to secure auxiliaryblade 400 to arm 130, 132. The surgeon may rotate locking wheel 135, 137in a direction opposite the first to release auxiliary blade 400 fromarm 130, 132.

With reference now to FIGS. 9A-9F, there are illustrated dissectors 500,600, 700 having various sizes configured for use with retractor system100. Each dissector 500, 600, 700 has a central passage 505, 605, 705extending along its length with open proximal and distal ends. Centralpassage 505, 605, 705 is configured and dimensioned such that dissector500, 600, 700 may slidably receive guide wire 1700 (FIG. 23) or guidepin therethrough. Guide wire 1700 or guide pin may guide dissector 500,600, 700 to slide therealong, as will be described below. In addition,each dissector 500, 600, 700 has indicia indicating depth of the bodycavity or the distance between the epidermal tissue surface and thevertebral body. The surgeon may utilize such indicia to select anappropriate retractor blade. In one embodiment, central passage 505,605, 705 is defined by an electrically conductive tube with plastic overmolded onto and surrounding the tube. A notch 610, 710 is formed in theproximal portion of dissector 600, 700 to expose a portion of the tubeshould a surgeon desire to use dissector 600, 700 in association with anelectromyography system in a known manner. A clip from theelectromyography system can be contacted with the conductive tube at theproximal notch, with the signal transmitted along the tube inside theinsulating plastic outer body, to the distal tip of the conductive tubewhich contacts tissue.

With reference now to FIGS. 10-12, there is illustrated a spinalinterbody spacer 900 for use with retractor system 100 for placementbetween vertebrae. Spacer 900 includes a pair of opposing sidewalls 960,962, a blunt nose 970, and an arcuate proximal wall 926. Spacer 900 ismonolithically formed and is made of any suitable biocompatible materialsuch as polyetheretherketone (PEEK), polysulfone (RADEL), polyetherimide(ULTEM), stainless steel, cobalt chrome, titanium, and titanium alloys.

Interbody spacer 900 defines a generally torpedo-shaped profile with anopening 928 extending therethrough to permit bone growth betweenadjacent vertebrae. In addition, opening 928 may contain additional bonegraft material. Blunt nose 970 includes substantially contoured, taperedsurface to facilitate insertion thereof between the vertebral bodies.Spacer 900 includes vertebral body engaging top and bottom surfaces 922,924 having protrusions configured to facilitate gripping and securing ofspacer 900 with adjacent vertebra. In particular, the protrusionincludes ring-patterned protrusions 944 concentrically arranged withrespect to opening 928. In addition, ring-patterned protrusions 944 ofopposing top and bottom surfaces 922, 924 may be configured to enablesecure engagement with respect to each other when disposed in asuperposed relation.

With particular reference to FIG. 12, arcuate proximal wall 926 includesa recess 930 defining a threaded aperture 935 for mating with aninsertion tool 50 (FIG. 14). Top and bottom surfaces 922, 924 of spacer900 are substantially parallel to one another. However, it is alsoenvisioned that in another embodiment of a spacer 1900 top and bottomsurfaces 1922, 1924 of spacer 1900 may contain lordosis and are notsubstantially parallel (FIGS. 13A and 13B). Further still, spacer 900may be tapered laterally defining a generally wedge shapedconfiguration. In particular, one sidewall may have a height that isdifferent from the height of the opposing sidewall defining the taperedor lordotic configuration. Alternatively, the opposing sidewalls mayhave the same height, and thus defining a parallel configuration.

With reference to FIGS. 14 and 15, insertion tool 50 may be utilized toinsert spacer 900 between vertebral bodies. Insertion tool 50 includes ahousing 52 having a tubular member 53 extending therefrom. A handle 54extends from housing 52 and is orthogonal to tubular member 53. Acoupling 55 is disposed at a distal end 51 of tubular member 53 and isconfigured and adapted for mating with arcuate proximal wall 926 ofspacer 900. A lumen 56 extends from distal end 51 of coupling 55 to aproximal end 57 of housing 52. Inserter rod 70 is repositionable throughhousing 52 and tubular member 53. Inserter rod 70 has a threaded portion72 at its distal end 71 that is configured for threadably engagingthreaded aperture 935 of spacer 900. A knob 74 is disposed in oppositionto threaded portion 72 with a shaft 75 extending therebetween.

It is also envisioned that if additional support for retractor 100system is necessary, a table mounted surgical arm (not shown) may beattached to the frame with the use of a stabilization arm adapter 1600(FIG. 8). It is further contemplated that illumination structure such asfiber optics, LED, may be utilized with retractor blade 200 to assist invisualization. Alternatively, a portion of blade portion 208 ofretractor blade 200 may be clear plastic and act as light channelsthemselves.

In use, the clinician positions the patient in a lateral decubitusposition on an operating table having a table break such that thepatient's iliac crest is directly over the table break. The patient maybe secured in position using tape at several locations while avoidingundue pressure points. The clinician uses fluoroscopy or another imagingmodality to identify the correct operative level and makes one or moreincisions through the patient's skin using conventional instruments. Thenumber and type of incisions made (e.g. transverse or vertical) isrelated to the procedure to be performed. Subsequently, the subcutaneoustissue layers are taken down exposing the oblique fascia. The musclefibers are carefully separated as a finger is advanced into theretroperitoneal space. The peritoneum is safely released anteriorly asthe retroperitoneal space is further developed. Finger palpation of thepsoas muscle or the anterior tip of the transverse process is used toconfirm proper location.

Once verified, dissector 500 (FIG. 9A) is introduced into the preparedpath and advanced through the psoas muscle, as shown in FIG. 24. Stayinganterior to the lumbar plexus, dissector 500 is docked directly into themiddle of disc “d,” as shown in FIG. 25. Thereafter, guide wire 1700(FIG. 23) is inserted through dissector 500 into disc “d,’ as shown inFIGS. 26 and 27. Dissector 500 is removed, leaving guide wire 1700 inplace, as shown in FIG. 28. One or more larger dissectors 600, 700 maybe introduced over guide wire 1700 to enlarge the opening, as shown inFIG. 30. The clinician may use, for example, a slight windshield wipermotion, anterior to posterior, to free up soft tissue. The clinicianmanipulates dissector 600 along the line of the muscle fibers of thepsoas, to thereby minimize trauma, as seen in FIG. 31. Advantageously,dissectors 600,700 are wider in one direction that the other (see FIG.9E), which facilitates insertion of the dissector between fibers of thepsoas muscle with the dissector oriented such that wider profile isaligned with the fibers and the thinner profile is oriented transverseto the psoas muscle fibers. Optionally, the surgeon may connect anelectromyography system to one or more of the dissectors to monitornerve activity during insertion and movement of the dissector.

After an adequate initial path to the spine is prepared in this mannerutilizing distractor(s), blade length may be determined by any one ofthe dissectors 500, 600, 700 in relation to skin level. The clinicianmay readily determine an appropriate blade length for retractor system100 by reading the indicia shown on dissector 500, 600, 700. Upondetermining the appropriate blade length, the clinician preparesretractor system 100 for use by selecting retractor blades with thedesired length and releasably attaching a pair of retractor blades 200to the first and second support 110, 120 of the retractor system 100.

Second support 120 is translated along the arms 130, 132 towards firstsupport 110 such that retractor blades 200 are in close cooperativealignment, as shown in FIG. 32A. The clinician then removes dissector600, 700 and inserts retractor system 100 with the closed retractorblades 200 into the prepared opening and along the longitudinal axis ofthe psoas muscle fibers. The retractor may be inserted over guide wire1700 with guide wire 1700 extending through a lumen defined bylongitudinal channel 209. Retractor system 100 is kept in line with themuscle fibers and advanced directly to the spine until the distal tipsof the blades are adjacent the spine, as shown in FIG. 33.Advantageously, the low profile of the closed retractor blades permitsthe blades to be worked between the fibers of the psoas muscle until thedistal tips of the blades pass through the psoas muscle and may bepositioned adjacent the vertebrae. Retractor system 100 is then turnedapproximately 90° so that the orientation of retractor blades 200 is inline with the endplates of the vertebrae, as shown in FIGS. 34A and 34B.

Once retractor system 100 is aligned with the retractor blades 200substantially transverse to the psoas muscle, retractor system 100 ismoved or retracted partially open so that the superior retractor bladeis disposed over the adjacent vertebral body, as shown in FIGS. 35A and35B. Optionally, one or more fixation pins 1000 (FIG. 21) may beintroduced through one or more of channels 209 of retractor blade 200and advanced into vertebra “V₁” using a fixation pin driver 1200 (FIG.22), as shown in FIGS. 36A and 36B. Preferably, fixation pin 1000 has athreaded distal portion 1020 for fixedly engaging bone structures and ahead 1040 that is operatively coupled to fixation pin driver 1200 forinserting or removing fixation pin 1000. With the superior blade affixedto the superior vertebra “V₁,” knob 122 is actuated to move firstsupport 110 away from second support 120, as shown in FIG. 37. However,it is also contemplated that with first support 110 affixed to thesuperior vertebra “V₁,” knob 122 may be actuated to move second support120 from first support 110. A slidable crank arm 123 (FIG. 1) may beextended outward from the knob 122 for additional cranking leverage. Asfirst support 110 moves away from second support 120, as shown in FIGS.38A and 38B, the ratchet associated with the second arm engages ratchetteeth 136 to prevent first support 110 from returning towards the secondsupport 120 under pressure from the retracted tissue. Retractor system100 is opened until adequate access and visualization of disc “d” isattained. If additional soft tissue retraction is desired, auxiliaryblades 400 for lateral aspect of retractor system 100 may be used. Inparticular, auxiliary blades 400 are inserted into the incision, drawnback along arms 130, 132 and locked into place by rotating locking wheel135, 137. The concave distal tips of the blades conform substantially tothe curvature of the side of the corresponding vertebra “V₁,” “V₂.” Thisshape advantageously minimizes soft tissue creeping under the blade tipto obstruct a portion of the operative channel. Fixation pins 1000assist in securing blades 200 to the vertebra to hold the distal bladetips in position against the vertebral bodies “V₁,” “V₂” to assure thatretracted tissue does not slip under blades 200 into the operative fieldas retractor system 100 is leveraged and manipulated during surgery.

An intradiscal shim 1300 (FIG. 16) may also be used to ensure minimalsoft tissue creep during instrumentation. Intradiscal shim 1300 isintroduced into channel 409 of auxiliary blade 400 and may be advanceddirectly into the disc space using a shim inserter tool 1400 (FIG. 17).Intradiscal shim 1300 is removed using an extractor tool 1450 (FIG. 18).

If additional stabilization is desired, an optional table mount arm 1600(FIG. 8) is attached to retractor system 100 and coupled to an externalsupport (not shown). Once the desired access is achieved, traditionalannulotomy and discectomy are performed as well as the release of thecontralateral annulus. A selection of disc preparation instrumentsincluding a variety of curettes, ronguers, rasps, chisels, and cobbs mayalso be used. In cases of extremely collapsed discs, a disc spreader1500 (FIGS. 19 and 20) having a flattened blade portion 1520 at a distalend 1510 thereof may be used to adequately distract the disc space.Blade portion 1520 may also include a plurality of markings 1530 thatindicate a distance from a distal end 1550 of blade portion 1520.Distraction is performed until the desired height is achieved. Ifimplant 900 is to be inserted into the intervertebral space, a series oftrial implants (not shown) may be used prior to deploying spinalinterbody spacer 900. Trial implants may be configured in both lordoticand parallel versions.

After the surgeon determines the appropriate type and size of interbodyspacer 900, interbody spacer 900 is inserted using implant insertiontool 50. The inserter rod 70 and handle 54 are coupled together and theselected spinal interbody spacer 900 is threaded on distal end 71 ofinserter rod 70 adjacent coupling 55 of distal end 51 of tubular member53. A mallet and slap hammer (not shown) may also be used to facilitateplacement of interbody spacer 900. Once spacer 900 is positioned in thedesired location, intradiscal shim 1300 and auxiliary blades 400, ifused, and any fixation pins 1000 are removed, ratchet release arm 124 isactuated to permit second support 120 to reapproximate towards firstsupport 110, and retractor system 100 is removed from the incision,which may be closed in a traditional manner.

It is within the scope of the present disclosure that fixation pins 1000may be used at any point during the procedure or they may not be used atall during the procedure. It will be understood that variousmodifications may be made to the embodiments of the presently disclosedlateral access system. For example, it is also contemplated that thespacer can be inserted over a rail system such as that shown in U.S.Pat. No. 7,615,079 to Flickinger et al., the contents of which areincorporated by reference herein in their entirety. It is furthercontemplated that the spacer can be assembled in situ over rails on bothsides of the inserter with the tip of the inserter becoming a part ofthe implant as shown in U.S. Published Application US2009/0228110 toMcClintock, the contents of which are incorporated by reference hereinin their entirety. In addition, while the systems and methods of thepresent disclosure have been illustrated in the context of a singlelevel spinal fusion procedure, it is contemplated that the systems andmethods may be utilized for multiple level fusions or in a procedure inwhich an entire vertebra is removed and replaced with an appropriatelysized implant. Therefore, the above description should not be construedas limiting, but merely as exemplifications of embodiments. Thoseskilled in the art will envision other modifications within the scopeand spirit of the present disclosure.

What is claimed is:
 1. A kit for spinal surgery comprising: a retractordevice having: a first support; a second support movable between a firstposition adjacent the first support and a second position spaced apartfrom the first support; and first and second retractor blades releasablycoupled to the first and second supports, respectively, the first andsecond retractor blades assuming a position in close approximation whenthe first and second supports are in the first position, and a second,open position when the first and second supports assume the secondposition spaced apart from one another, the distal end portion of theretractor blades configured and dimensioned to engage a vertebral body;a dissector; a guide wire; and a fixation pin.
 2. The kit according toclaim 1, further including a surgical implant.
 3. The kit according toclaim 2, further comprising a disc spreader.
 4. The kit according toclaim 1, wherein the recess defined in the distal end portions of therespective first and second retractor blades include an arcuate portionhaving a radius of curvature substantially identical to that of thevertebral body.
 5. The kit according to claim 4, wherein the radius ofcurvature is in the range from about 0.1 inch to about 1.0 inch.
 6. Thekit according to claim 1, wherein the first and second retractor bladeseach define a longitudinal groove, whereby when the first and secondretractor blades are in a close cooperative position the grooves definea lumen.
 7. The kit according to claim 6, wherein the longitudinalgroove is configured and dimensioned to receive therethrough a fixationpin.
 8. The kit according to claim 1, further comprising an auxiliaryblade adapted to be transversely mounted on one of the first and secondretractor blades.
 9. The kit according to claim 8, wherein the auxiliaryblade includes a longitudinal groove.
 10. The kit according to claim 8,further comprising an intradiscal shim adapted to engage thelongitudinal groove of the auxiliary blade.
 11. The kit according toclaim 1, wherein the dissector includes indicia thereon marking thedistance from a distal end of the dissector.